TALLAHASSEE, Fla., Nov 6 - Hotly contested battles in Georgia and Florida pitting liberal black Democrats against white Republicans supported by President Donald Trump headline the three dozen governors' races being contested in Tuesday's U.S. elections.In Georgia, Stacey Abrams is vying to become the nation's first black female governor. The 44-year-old Georgia politician and Andrew Gillum, the mayor of Tallahassee, Florida, would also be the first black governor in each of their states.Abrams and Gillum, 39, are testing a new liberal path in Southern states where traditional, centrist Democrats have repeatedly lost. They seek to rally greater numbers of young voters and minorities, who typically favor Democrats but often sit out elections in years when a presidential vote is not held.Trump's reputation is on the line in Georgia and Florida after his endorsements helped Georgia Secretary of State Brian Kemp and former Congressman Ron DeSantis of Florida clinch the Republican nominations for their states' open gubernatorial seats.Accusations of race-baiting have dogged Kemp, 55, and DeSantis, 40. They deny the charges.Gillum, joined by his wife and three young children, cast his ballot on a drizzly morning in Tallahassee, the capital of Florida. Afterward, he said his election would send a message to Trump "that the politics of hatred and of division, of separation, that they've come to an end.""We're returning the politics of decency and what's right and what's common between all of us," he told reporters in a voice hoarse from campaigning. "We'll worry about history later, but today we're working to win."DeSantis, after voting in Ponte Vedra Beach, told reporters: "We did as much as can be done and I'm happy. Let the chips fall where they may."While much of the focus of Tuesday's elections is on which party wins control of the U.S. Congress, Republicans and Democrats are battling across the country for state-level power, which can help them support or resist Trump's agenda on issues such as healthcare, gun control and gay rights.Democrats, playing catch-up after a net loss of 13 governorships and more than 900 state legislative seats during the eight-year Obama administration, are fielding their largest slate of legislative candidates in more than three decades.Republicans currently control 33 governors' mansions and two-thirds of state legislative chambers.The outcome of elections for state positions could also affect future control of the U.S. House of Representatives.Governors and hundreds of legislators elected this year will be in office when congressional districts are redrawn after the 2020 Census. In some states, a governor's power to sign or veto congressional maps could decide the partisan balance.DEMOCRATIC GAINS EXPECTEDJennifer Duffy, who analyzes governors' races for the nonpartisan Cook Political Report, expects Democrats to wrest between six and eight governorships away from Republicans, who are defending a large number of open seats in battleground states.Critical contests are taking place in Midwestern and Rust Belt states that sealed Trump's 2016 victory, where Republican losses could hurt his re-election chances in 2020.Opinion polls show Democratic gubernatorial candidates leading or highly competitive in Michigan, Pennsylvania and Wisconsin. These states typically vote Democratic in presidential elections but in 2016 swung to Trump, securing his win in the Electoral College system that tallies wins in states, even as he lost the national popular vote.Republicans are also fighting tough races in several states considered conservative strongholds in the north and central Great Plains."The eyebrow-raiser will be if Democrats pick up a South Dakota, Kansas, Oklahoma - these sort of very, very red (Republican) states," Duffy said, noting local dynamics, rather than national politics, were mostly responsible for Republican weaknesses.Republicans, however, could gain in Democratic territory and pick up a pair of governors' seats in Oregon and Connecticut.Opinion polls show tight races in Georgia and Florida, where the current Republican governors cannot run again due to term limits.Trump traveled to each state in the closing days of the campaign to energize Republicans at "Make America Great Again" rallies. Democratic former President Barack Obama swooped in to boost the Democrats, and media star Oprah Winfrey visited Georgia on behalf of Abrams.In Georgia, critics have drawn attention to Kemp's dual role as a candidate for governor and as supervisor of the state's elections in his capacity as secretary of state. Kemp accused Democrats on Sunday of trying to hack voter registration systems, without offering any supporting evidence. Democratic Party officials, who have accused Kemp of trying to suppress the minority vote, quickly denied the charge.A nonprofit group, Protect Democracy, said it had filed an emergency lawsuit on Tuesday asking a federal judge to block Kemp from presiding over the election results, including any recount or runoff race.Under Georgia law, if neither Abrams nor Kemp wins a majority of the vote on Tuesday, their battle continues to a December runoff. The presence of a third-party candidate on the ballot makes that possibility more likely.In Florida, the rancor of the current political climate weighed on Bob Marky of Tallahassee as he voted for Gillum for governor. The 54-year-old house painter, a Democrat, said he also supported candidates from both parties for local office."I just was looking for a change," he said. "The political environment has gotten a little out of hand."